Recently, development in communication technology has encouraged users to build home networks to link different rooms in a house. A home server system is built by connecting home information appliances to a home network. In a home server system, the home server manages the state of home information appliances and also controls the state thereof. Meanwhile, the widespread use of cell phone terminals with a built-in data communication client has made mobile computing a reality. In mobile computing, cell phone terminals are connected to a server via a network and perform data communication with the server. By blending home server systems and mobile computing, users are capable of accessing home servers using cell phone terminals and controlling the illumination or refrigerator in the house even when the users are away from the house (see, for example, patent document No. 1).    [patent document No. 1] JP 2003-298659